Diaphragm for talking-machines.



No. 855,562. PATENTED JUNE 4, 1907. T. A. EDISON.

DIAPHRAGM FOR TALKING MACHINES. APPLICATION FILED'MAR.6,1907.

* UNITED STATES PATENT @FFIOE.

THOMAS A. DISO or LLEWELLYN ARE, ORANGE, NEW JERSEY, ASSIGNOR TO NEW JERSEY PATENT eOMPANY, OF WEST ORANGE, NEW JERSEY, A eORrORATiO OF N W JERSEY.

DIAPHRAGM FOR rALKlNe MAoHmEs. A

Specification of Letters Patent.

Patented June 4, 1907.

'Applieation filed March 6,1907 Serial No. 360.936.

be readily responsive to vibrations of com' paratively great amplitude.

WVith diaphragms as now made in the form of a continuous disk (or a series of disks of decreasing diameters) clamped rigidly at its edge, the extent of the amplitude to which the diaphragm is capable' of vibrating is neccssarilyvery limited, since the material of which it is formed is not only flexed as the diaphragm vibrates on either side 01'' the medial line, but undergoes stretching and contraction as it moves'away from or toward the medial line. This limited capacity of the diaphragm to partake of any considerable degree of amplitude, limits in a measure the loudness of the reproduction. If it were attempted to remedy this defect by increasing the diameter of the diaphragm or materially reducing its thickness, the reproduction would not be increased but would become more or less flabby or hollow.

Another difiiculty encountered with diaphragms as now constructed is than the resistance to the vibrating effect is not uniform as the diaphragm moves to either side of the medial line, but enormously increases with the amplitude, so that even if such diaphragms were capable of vibrating to a considerable extent, the power available to operate them would be insufficient to'ellect that result without incurringundue wear on the record suriace. To el'l'ect a materially increased amplitude,l propose the making of a diaphragm in which these. two diiiiculties are very largely removed,'sinee the diaphragm will be capable of being vibrated to a much greater amplitude than is now possible, while the resistance to the vibration does not materially or objectionably increase within reasonable limits on either side of the medial hne.

plex diaphragm made of at least two disks, each of which is radially slotted so that eac disk will constitute a series of reeds, and the slots of the disks being staggered so that a continuous surface will be presented for actuating the sound waves. Said disks are preferably cemented together by means of an elastic cement, such as a solution of gum rubber, in order to prevent undue resistance in vibrating. If two disks as above described were alone used, each of the reeds would be flexed throughout substantially its entire length, whereas the best results are obtained if the ilexure is substai'itially limited to the base of each reed, so that each reed will substantially vibrate as a whole. To secure this ellect 1 preferably form each section of the duplex diaphragm of a series of disks, say three in number, of gradually reduced diameter, whereby the vibration will be practically limited to the thinnest or outer portion. Having constructed a diaphragm of-two disks or series of disks as explained, the central opening formed therein is closed by a pair of light corrugated disks seated on rubber gaskets and with which connection is made to the recording or reproducing stylus.

' In order, that the invention may be better understood attention is directed to the accompanying drawing forming part \of this specification, and in which Figure 1 is a plan view of the improved dialine 22 ofFig. 1.

in both of these views the same parts are merais.

As shown, the diaphragm in its preferred form is composed of two disks, 1 and 2, and supplemental disks 1 1 and and 2". '1 he disks forming the section 1, 1, 1 and the section 2, 2 and 2 are first cemented together as in the manufacture of ordinary laminated diaphragms, said disks being each formed preferably of mica about one-thousandth of an inch thick. After each or the phragm, and Fig. 2 is a sectional view on the laminated sections is thus constructed, a cen-' To this end the invention comprises a durepresented by corresponding reference nu- TOO v The slots 3 the free vibration of thereeds formed by slotting the same, may not be interfered with, I make use of a pair of light metal disks 5 5, corrugated as shown so as to be as stiff as possible, and made preferably of aluminium or metallic magnesium, and these disks are seated on rubber gaskets Q and are held together by a very small bolt 7 and .nut 8. l/Vith the bolt 7 the usual connection to the recorder or reproducer diaphragm may be made.

Having now described my invention what I claim as new therein, and desire to secure by Letters Patent is as follows:

1. A diaphragm for talking machines formed of two sections, each having radial slots and the slots of one section being staggered with relation to the slots of the other section, substantially as and for the purposes set forth.

2. A diaphragm for talking machines comprising two sections cemented together, each section 'bein radially slotted and the slots of one section eing staggered with relation to the slots of the other section, substantially as and for the purposes set forth.

3 A diaphragm for talking machines comprising two laminated sections, each formed with radial slots and the slots of one section being staggered with relation tothe slots 0i the other section, substantially as and for the purposes set forth;

4. A diaphragm for talking machines formed with radial slots so as to result in the production of a series of reeds, and means for closing said slots without materially affecting the vibrating capacity of said reeds, substantially as and for the purposes set forth.

5. A talking machine diaphragm provided with radial slots so as to form a series of reeds and a disk secured to the diaphragm andclosing said slots without materially affecting the vibrating capacity of the reeds, substantially as and for the purposes set forth.

6. A talking machine diaphragm provided with a central opening and a series of radial slots, of a disk secured to the diaphragm so as to cover the central opening, substantially as and for the purposes set forth.

7. A talking machine diaphragm provided with a central opening and a series of radial slots, of a disk secured to the diaphragm so as to cover the central opening, said disk being seated on an elastic gasket, substantially as and for the purposes set forth.

8. A talking machine diaphragm formed with a central opening and a series of radial slots, of a pair of metallic disks connected together and engaging the opposite faces of the diaphragm and covering said opening, substantially as and for the purposes set forth.

This specification signed and witnessed this 23rd day of February1907.

THOS. A. EDISON. 

